Pressure Surge Research Articles

Chance-constrained vulnerability assessment of smart water distribution systems against stealthy false data injection attacks

Smart water distribution systems (SWDSs) have not only enhanced the monitoring and control of the entire water infrastructure but have also jeopardized its security and resilience. The state-of-the-art examined the uncertainties in the water supply network to obtain optimal design parameters to ensure hydraulic integrity. However, the investigations of uncertainties in SWDSs from the cybersecurity perspective remain unexplored. To address this limitation, this paper utilizes a robust chance-constrained optimization strategy to scrutinize the vulnerable location of SWDSs against False Data Injection (FDI) attacks. This is achieved by factoring in the probabilistic behavior of water demand at junctions that can potentially facilitate stealthy FDI attacks on the hourly measurements of the pump’s flow rate. The proposed nonlinear model is validated with several case studies reflecting the real-world cyberattack consequences including cutoff water supply of the network, enhanced power consumption of the pump, and the undesirable pressure surge in the system at strategic locations of SWDSs. As a result of the studied cases, the cyberattack consequences on the entire water supply network are obtained while highlighting the threat-prone regions of the network. This paper contributes to embedding additional security layers to the existing water infrastructure at the vulnerable links and junctions.

Calculation of a cavitation device for industrial water treatment

Relevance. Currently, the issue of preventing pollution of the hydrosphere by industrial wastewater, the use of new effective technologies for industrial water purification and its reuse in production is extremely acute. In this regard, the urgent tasks are the search and implementation of new methods of water treatment: innovative technologies, disinfection and desalination of water, methods of its reuse.Methods. The article proposes a new technology for water treatment – the cavitation effect on the flow is enhanced by the shock effect of a pressure surge, which makes it possible to suppress the vital activity of microorganisms in the water. On the basis of the developed workflow, its mathematical model and the author’s methodology, calculations were made for three hydrodynamic cavitation devices with a pressure jump in order to disintegrate sulfate-reducing bacteria in industrial waters.Results. In accordance with the terms of reference (nominal fluid flow Q, nominal absolute pressure before installation P1, allowable pressure drop on the device ΔP, nominal fluid temperature t, physical properties of the medium) based on the proposed working process of a hydrodynamic cavitation device that forms a supersonic flow with a transition to subsonic through a pressure jump, an appropriate mathematical model and an adequate technique, the regime and geometric parameters of three pilot samples of hydrodynamic cavitation devices designed to destructurize sulfate-reducing bacteria in industrial waters were calculated. In order to form a supersonic flow in the installation under sufficiently strict conditions for ensuring permissible pressure drops, a nozzle was profiled with a minimum drag coefficient along the Vitashinsky curve. Industrial testing of cavitation devices showed good convergence of theoretical and experimental data: the suppression of bacteria was carried out by 80–100%.

Identification and prediction of hydrate–slug flow to improve safety and efficiency of deepwater hydrocarbon transportation

The vast hydrocarbon resources (oil, gas, and gas hydrate) in deepwater areas are considered one of the most significant resources of the future. However, the dangerous flow patterns and blockage accidents caused by hydrates threaten the safety and efficiency of the transportation process. A mutual interaction exists between hydrate growth and multiphase flow. In this study, hydrate formation and gas–slurry two–phase flow tests were conducted in a pure water system with a constant pressure (4 MPa) and various liquid loadings (40–80%) in a visual flow loop. It was found that the hydrate growth process in the dynamic system included bubble promotion, subcooling promotion, and mass transfer inhibition. Meanwhile, two atypical slug patterns (rapid conversion slug and deposition slug) in the vertical upward flow were determined, which corresponded to the promotion and inhibition regions. In the rapid conversion slug flow, the churn segments replaced the original Taylor bubbles when the liquid loading was less than 60%. In the deposition slug flow, slurry shedding phenomena was observed. In addition, the hydrate particle deposition behavior was found to inhibit hydrate growth and cause flow pattern shifts, but did not trigger the differential pressure surge. The gas isolation caused by the liquid plug and energy dissipation due to the collision between hydrate particles and the tube wall may be responsible for the sudden increase in pressure drop. Furthermore, the feasibility of predicting hydrate blockage using the differential pressure method was explored. The experiment results showed that this warning method was effective when the liquid loading was below 76%. And an effective warning can improve the transport capacity by approximately 34%.

Failure of 24 Inches Blowdown Tower Inlet Nozzle Due to Cyclic Surge Forces

Blowdown tower is one of the equipment in closed blowdown system (CBS) in Delay Coker unit in petroleum refinery. The primary intended function of the CBS is to flush out hydrocarbon vapours from coke drum using high pressure steam into blowdown tower. The system is operating in batches and cycles, due to constant operation at various temperature, pressure, and conditions, components are susceptible to various of failures including thermal fatigue, crack, corrosion, and others. Crack incident was observed on the welding of blowdown tower nozzle that connected to closed blowdown system (CBS) piping after 11 years of operation. This paper aims to study the structural integrity and risk level of the CBS system in relation to liquid level in receiving tower (blowdown tower). Dynamic piping stress analysis and Finite Element Analysis (FEA) was conducted on this line and blowdown tower nozzle to evaluate the overall material behaviour and assessed the risk of failure. The acceptance criteria of the analysis were set to be based on ASME VIII-Division 2 part 5.2.2 (Elastic Stress Analysis Method) and ASME II-part D. Findings from FEA shows that the failure occurred on the blowdown tower nozzle was due to surge pressure impact from high pressure steam flow to obstructed high liquid elevation at the inlet nozzle. The high surge pressure that happened near the nozzle has caused the stress to exceed allowable level thus initiated the crack in cyclic/ batch service. It is recommended that petroleum refinery to continuously maintain the blowdown tower level below nozzle to prevent similar phenomenon to happen in future.

O011 Exploring Nocturnal Blood Pressure Surges Relationships with Brain Health and Cognitive Function.

Abstract Introduction Cerebral small vessel disease is a possible mechanism to explain the link between long-term incompletely treated obstructive sleep apnoea (OSA) and dementia. Recent evidence suggests nocturnal blood pressure (BP) surges triggered by OSA-related sympathetic hyperactivity could play a critical role. However, this remains to be determined as they often occur concurrently with desaturation events. Methods During an in-lab polysomnography study of 7 controls [AHI≤5] and 20 untreated OSA patients [AHI>5] aged 45-65 years the frequency of blood pressure surges (>10% systolic ↑BP) in the presence or not of desaturation events (↓SpO2>3%) were quantified with a SOMNOtouch™ NIBP device. Cerebral perfusion was assessed with pCASL MRI and brain lesions with anatomical MRI scans. The global deficit score was determined for cognitive function assessment. Inflammation was quantified with blood hs-CRP. Results After controlling for age, BMI, gender, blood glucose and cholesterol, higher AHI was associated with more frequent BP surges (r=0.52, P=0.03), BP surges occurring with desaturation events (r=0.87, P<0.001), but not with BP surges without oxygen desaturation (P = 0.11). Concurrent BP surges and oxygen desaturation was associated with increased hs-CRP (r=0.55, P=0.02). Frequency of BP surges was not related to cerebral perfusion, brain lesions or the global deficit score. Conclusions Recording nocturnal blood pressure surges during polysomnography may provide insight into the cardiovascular burden associated with OSA. Interestingly, an inflammatory response is associated with BP surges only during desaturations, i.e. during respiratory events. Further work is needed to assess the utility of BP surges in predicting longer-term cognitive deficits.

Swab – Surge Pressure Investigation, and the Influence Factors, Prediction and Calculation (Review)

Surge pressure is supplemental pressure because of the movement of the pipes downward and the swab pressure is the pressure reduction as a result of the drill string's upward movement. Bottom hole pressure is reduced because of swabbing influence. An Investigation showed that the surge pressure has great importance for the circulation loss problem produced by unstable processes in the management pressure drilling (MPD) actions. Through Trip Margin there is an increase in the hydrostatic pressure of mud that compensates for the reduction of bottom pressure due to stop pumping and/or swabbing effect while pulling the pipe out of the hole. This overview shows suggested mathematical/numerical models for simulating surge pressure problems inside the wellbore with adjustable cross-section parts. The developed models require simple input data that may be gotten from the rig location. Pressure variations due to Swabs and surge has been a major concern in the oil industry for numerous years. If the pressure variations become moreover extraordinary, this leads to formation fracture, and formation influx principal to a kick. In the worst circumstances and situations that kick principal on the blowout and put crew life in hazard. By using theoretical investigation and experimental consequences, it established that the surge pressure is a function of the well depth, the drilling tools combination, the diameter of the wellbore, drilling mud properties, drilling pipe operation speed, and acceleration of the drill pipe movement, etc. This review focuses and investigates the essential theory and on software that computes the pressure variations in different flow conditions to predict surge and swab pressure values.

Analysis of pressure surges under various flow patterns in the tunnel of an underwater rock plug blasting system using different transition process models

Abstract The pressure surge at the moment of blasting seriously threatens the safety of pipeline structures and other buildings. This article established two numerical simulation models of the hydraulic transition process and water–air two-phase flow based on the one-dimensional transient flow theory and considering the actual flow characteristics of water and air. The hydraulic characteristics and blasting parameters of the blasting system were studied under two different conditions of the tunnel with and without the pressure flow. The observed parameters of an actual blasting engineering prototype verified the accuracy of the mathematical model. The maximum pressure of pressure blasting was 2.55 times as high as hydrostatic pressure. The maximum pressure of non-pressure blasting was 1.77 times as high as hydrostatic pressure. Pressure blasting impact was 2.17 times greater than nonpressure blasting. Discrepancies between actual and simulated data for gushing and overflow heights ranged from 9 to 14%. The model can provide a reference for blasting engineering on the simulation calculation of hydraulic characteristics such as impact pressure, overflow time, and overflow of the underwater rock plug blasting system.

Association between Morning Surge and Left Ventricular Hypertrophy in Obese Hypertensive Patients.

Weight gain can trigger mechanisms that increase blood pressure. Nevertheless, obesity causes structural changes in the myocardium, including increased ventricular mass, atrial dilatation, and diastolic and systolic dysfunction. Additionally, blood pressure variations, like morning surge (MS) in obese hypertensive patients may have clinical relevance in cardiovascular events. Although morning blood pressure surge is a physiological phenomenon, excess MS can be considered an independent risk factor for cardiovascular events. To evaluate MS values and their association with left ventricular hypertrophy (LVH) and nocturnal dipping (ND) in obese and non-obese hypertensive patients. A cross-sectional study that evaluated BP measurements by ambulatory blood pressure monitoring (ABPM) and the presence of LVH by echocardiography in 203 hypertensive outpatients, divided into two groups: 109 non-obese and 94 obese hypertensives patients. The significance level was set at 0.05 in two-tailed tests. A MS above 20 mmHg by ABPM was detected in 59.2% of patients in the non-obese group and 40.6% in the obese group. LVH was found in 18.1% and 39.3% of patients in the non-obese and obese groups, respectively, p<0.001. In the "obese group", it was observed that a MS>16 mmHg was associated with LVH, [prevalence ratio: 2.80; 95%CI (1.12-6.98), p=0.03]. For the non-obese group, the cut-off point of MS for this association was >22 mmHg. High MS was positively associated with LVH, with a particular behavior in the hypertensive obese group.

Supercritical CO2 compressor operation near stall and surge conditions

Instabilities such as stall and surge have been widely studied in open loop gas turbine system for several decades. However, researches on instabilities in a closed loop are limited. Especially, no experimental investigation in a supercritical CO2 compressor has been performed thoroughly before. An integral test loop equipped with a turbo-alternator-compressor using active magnetic bearing was utilized to study the instabilities in a supercritical CO2 compressor. The compressor performance testing was conducted including near stall and surge operating conditions. The mass flow rate of compressor was greatly reduced even beyond surge limit and pressure was measured with high frequency transducer to observe the characteristics. It was observed that as the inertia of the system was changed by altering the compressor inlet conditions, the characteristics of the supercritical CO2 compressor in unstable operating conditions also vary. This can be qualitatively explained by using the theory Greitzer proposed previously.

Renal tubular SGK1 is required to achieve blood pressure surge and circadian rhythm.

Blood pressure (BP) follows a circadian pattern that rises during the active phase of the day (morning surge) and decreases during the inactive (night dipping) phase of the day. The morning surge coincides with increased circulating glucocorticoids and aldosterone, ligands for glucocorticoid receptors and mineralocorticoid receptors, respectively. Serum- and glucocorticoid-induced kinase 1 (SGK1), a clock-controlled and glucocorticoid receptor- and mineralocorticoid receptor-induced gene, plays a role in BP regulation in human and animal models. However, the role of SGK1 in BP circadian regulation has not yet been demonstrated. Using telemetry, we analyzed BP in the inducible renal tubule-specific Sgk1Pax8/LC1 model under basal K+ diet (1% K+) and high-K+ diet (HKD; 5% K+). Our data revealed that, under basal conditions, renal SGK1 plays a minor role in BP regulation; however, after 1 wk of HKD, Sgk1Pax8/LC1 mice exhibited significant defects in diastolic BP (DBP), including a blunted surge, a decreased amplitude, and reduced day/night differences. After prolonged HKD (7 wk), Sgk1Pax8/LC1 mice had lower BP than control mice and exhibited reduced DBP amplitude, together with decreased DBP day/night differences and midline estimating statistic of rhythm (MESOR). Interestingly, renal SGK1 deletion increased pulse pressure, likely secondary to an increase in circulating aldosterone. Taken together, our data suggest that 1) the kidney plays a significant role in setting the BP circadian rhythm; 2) renal tubule SGK1 mediates the BP surge and, thus, the day/night BP difference; 3) long-term renal SGK1 deletion results in lower BP in mutant compared with control mice; and 4) renal SGK1 indirectly regulates pulse pressure due to compensatory alterations in aldosterone levels.NEW & NOTEWORTHY Dysregulation of blood pressure (BP) circadian rhythm is associated with metabolic, cardiovascular, and kidney diseases. Our study provides experimental evidence demonstrating, for the first time, that renal tubule serum- and glucocorticoid-induced kinase 1 (SGK1) plays an essential role in inducing the BP surge. Inhibitors and activators of SGK1 signaling are parts of several therapeutic strategies. Our findings highlight the importance of the drug intake timing to be in phase with SGK1 function to avoid dysregulation of BP circadian rhythm.

The Relationship between Nocturnal Dipping Status, Morning Blood Pressure Surge, and Hospital Admissions in Patients with Systolic Heart Failure.

Hypertension is a known risk factor for developing heart failure. However, there is limited data to investigate the association between morning blood pressure surge (MBPS), dipping status, echocardiographic parameters, and hospital admissions in patients with systolic heart failure. To evaluate the relationship between morning blood pressure surge, non-dipper blood pressure pattern, echocardiographic parameters, and hospital admissions in patients with systolic heart failure. We retrospectively analyzed data from 206 consecutive patients with hypertension and a left ventricular ejection fraction below 40%. We divided the patients into two groups according to 24-hour ambulatory blood pressure monitoring (ABPM) results: dippers (n=110) and non-dippers (n=96). Morning blood pressure surge was calculated. Echocardiographic findings and hospital admissions during follow-up were noted. Statistical significance was defined as p < 0.05. The study group comprised 206 patients with a male predominance and mean age of 63.5 ± 16.1 years. The non-dipper group had significantly more hospital admissions compared to dippers. There was a positive correlation between MBPS and left atrial volume index (r=0.331, p=0.001), the ratio between early mitral inflow velocity and flow propagation velocity (r= 0.326, p=0.001), and the ratio between early mitral inflow velocity and mitral annular early diastolic velocity (E/Em) (r= 0.314, p=0.001). Non-dipper BP, MBPS, and E/Em pattern were found to be independently associated with increased hospital admissions. MBPS is associated with diastolic dysfunction and may be a sensitive predictor of hospital admission in patients with systolic heart failure.

Predicting Blood Pressure Surge With Alarm In Firefighters

Predicting Blood Pressure Surge With Alarm In Firefighters

HOUSING INFORMALITY IN THE GLOBAL SOUTH: Insights from a Policy Comparison between Accra and Buenos Aires

AbstractInformal settlement growth in various countries has led to distinctive actions that enhance low‐income populations’ accessibility to adequate, safe and affordable housing and basic services. This trend indicates the need for comparative studies between countries and cities to understand the factors that lead to policy learning opportunities. We conducted an experimental comparison between Accra, Ghana, and Buenos Aires, Argentina, to understand, first, how policies on informal settlements have been formed, and secondly, what inquiries should be made to address housing informality in the global South. A comparison shows that these cities/countries have shared moments of neoliberalization and that their poor residents have experienced similar struggles regarding housing availability and the pursuit of extensive governmental interventions. Therefore, their experiences are worth examining. Our comparison indicates that first, Buenos Aires/Argentina has adopted more inclusive policies regarding informal dwellers than Accra/Ghana, and secondly, that diversifying housing solutions are an inevitable dynamic in cities/countries experiencing a surge in housing pressure across classes, races and geographies. In this article we articulate how the governments of these countries have dealt with these challenges and conceptualize the coproduction needs of housing informality in developing countries. We encourage policymakers facing informality in the South to respond to the questions we raise about facilitating policy learning.

Effect of Modified Peristaltic Phacoemulsification Device on Efficiency and Post-Occlusion Pressure Surge.

To evaluate efficiency of grooving, nuclear fragment removal, and changes in pressure control in the Oertli Faros using traditional peristaltic and Speed and Precision (SPEEP) features. The SPEEP mode uses novel peristaltic technology permitting independent control of flow and vacuum. A porcine lens model was used with an enclosed chamber simulating the anterior segment. Grooving efficiency is evaluated with flow rates of 10, 30, and 50 mL/min using whole lenses. Lens cubes were emulsified at 20, 40, 60, 80, and 100% power with both SPEEP and non-SPEEP modes. Surge was evaluated with pressure gauges placed on the irrigation tubing and aspiration tubing. Pressure readings were recorded per the following: fluid and vacuum were initiated for 15 seconds, vacuum tubing was occluded for 5 seconds, tubing patency was then re-introduced for 15 seconds. Differences between sensors were recorded. No significant increase in efficiency was seen with increasing flow rate from 30 to 50 mL/min using SPEEP. No significant differences were shown in lens fragment removal in SPEEP and non-SPEEP modes at any power tested. Pressure difference measurements were not significantly different with SPEEP and non-SPEEP modes. We showed that lower flow rates show comparable efficiency of grooving when using the SPEEP mode. The SPEEP function did not show increased efficiency in nuclear fragment removal when compared to traditional mode. Surge control was also comparable with both SPEEP and non-SPEEP modes. We suggest that the SPEEP function included in the Oertli Faros may have some advantages.

The morning blood pressure surge in diabetic hypertensive patients with different dipper patterns

The morning blood pressure surge in diabetic hypertensive patients with different dipper patterns

How workload impacts the employee performance and how work stress acts as a mediating variable in shoes manufacturing company

The global industry has been significantly affected by Covid 19, resulting in a reduction in organizational structure, an increase in demand for raw materials and delivery services, and a rise in prices that negatively affect the manufacturing industry. The department responsible for managing these issues is the purchasing department, which will experience a surge in workload and work pressure for its employeesImproving employee performance is a challenge for companies to maintain survival. The thing that needs to be considered is the workload of employees which affects work stress and ultimately causes a decrease in employee performance. The main objective of this research is to examine the effect of workload on performance through work stress. Research using quantitative research methods. The questionnaire has been tested for validity and reliability and distributed to 110 purchasing employees. SmartPLS 3 is used to process data from research results. The results of the study are that there is a negative effect of workload on performance, there is a positive influence of workload on work stress, there is a negative effect from work stress on employee performance, and there is a negative effect of workload on performance through work stress on purchasing employees. The results of this study can be used by companies to improve their performance, especially from factors related to workload and employee work stress.

The relationship between morning blood pressure surge and serum IGF-1 level in acromegaly patients with hypertension.

High levels of insulin-like growth factor 1 (IGF-1) in patients with acromegaly cause structural and functional changes specific to the disease. These changes lead to mortality if the disease is not treated. Circadian blood pressure (BP) rhythm as measured by 24-h ambulatory blood pressure monitoring (ABPM) can change with a decrease in BP during sleep and a sudden increase in wakefulness. We aim to evaluate the relationship between changes in BP and IGF-1 levels in patients with acromegaly. Patients who were diagnosed with acromegaly and the patient group with hypertension were included. Serum biochemistry parameters, serum IGF-1 level and ABPM follow-ups were compared in these patients. In our study, 30 patients with acromegaly and 30 patients with hypertension without acromegaly were included. Thirty of the patients were male and 30 were female. There was a statistically significant difference between the groups in terms of IGF-1(p = < 0.001) and GH(p = 0.004). There was no significant difference between patients' office systolic/diastolic BP measurements, day/night, systolic/diastolic BP measurements and all systolic/diastolic BP measurements in ambulatory blood pressure follow-ups. There was a significant difference in morning blood pressure surge(p = < 0.001). A statistically significant difference was found between the acromegaly patient groups with MBPS below and above 25mmHg in terms of IGF-1 (p = 0.025) and platelet levels (p = 0.004). As a result, cardiovascular disease risks can be predicted in patients with high serum IGF-1 levels by planning ambulatory blood pressure in the early period.

Research on Managed-Pressure Running Casing in Oil and Gas Wells with the Negative Pressure Window

The failure of managed-pressure running casing in oil and gas wells may lead to complex accidents such as overflow or leakage. The technique of using multi-density gradient drilling fluids in wellbores with negative pressure windows (NPWs) is often used to deal with this situation. Therefore, it is vital to analyze the dynamic slurry column structure and calculate the wellbore pressure during casing running. For this issue, the model of transient surge pressure is established during casing running. The calculation equation of the model is proposed, and the calculations of the wellbore pressure are carried out with the exploration of Well LT-X1, located in the Xinjiang oil field. A circulation scheme is designed as follows: Circulate 125 m3 of drilling fluid with a density of 2.45 g/cm3 and 155 m3 of drilling fluid with a density of 2.35 g/cm3 at a depth of 3560 m. From there, circulate 164 m3 of drilling fluid with a density of 2.35 g/cm3 at a depth of 5900 m. Finally, at a depth of 7050 m, circulate 250 m3 of drilling fluid with a density of 2.30 g/cm3. The casing running speeds and back-pressure values were designed as follows for the respective well sections: 0–1523 m: 0.160 m/s casing speed, 0 MPa back pressure; 1523–3560 m: 0.160 m/s casing speed, 1.641 MPa back pressure; 3560–5900 m: 0.145 m/s casing speed, 2.427 MPa back pressure; 5900–6674 m: 0.137 m/s casing speed, 4.041 MPa back pressure; 6674–7050 m: 0.124 m/s casing speed, 4.457 MPa back pressure. The results show that optimizing structure of the multi-density gradient drilling fluid with different densities and applying annular back pressure in stages, with the accurate calculation of wellbore pressure, can achieve the goals of leak-proofing and pressure-stabilization. It is concluded that this result may serve as the foundation for managed-pressure running casing technology.

Turbulence in liquid phase and its influence on aeration and pressure surge in intermittent type two-phase flow

Nuclear industry considers intermittent type of two-phase flow as a complex flow pattern due to its intricate hydrodynamics. Turbulence causes aeration inside the liquid slug leading to sudden surge in pressure and large Reynolds stresses near the wall. This result in high mechanical impact associated with structural vibration and erosion-corrosion in the pipeline. Fast accelerated corrosion associated with high momentum of slug and aeration in the slug body leads to cracks in the pipeline. In order to avoid hazardous accidents in nuclear industry associated with leakages from these cracks, a detailed analysis of the phenomena of aeration in the liquid slug is vital. The present work reports how turbulence in the liquid phase leads to aeration and its augmentation in the slug. In the first part of the present article, flow visualization analysis is presented depicting that at low level of turbulence, aeration is absent in plug flow regime. Increase in level of turbulence in liquid phase causes aeration and its augmentation in slug. The second part deals with analysis of the measured instantaneous averaged velocity variations in the liquid phase using Laser Doppler Velocimetry (LDV). The turbulence characteristics in the liquid phase measured using LDV is used to depict the cause of aeration in slug and its consequences on the pressure fluctuations. Instantaneous pressure signals and the pressure drop per unit length are measured in plug, less aerated slug (LAS) and high aerated slug (HAS) regime and correlated to the turbulence characteristics. At the end, the consequence of turbulence and pressure surge on pipe failure are depicted.

Acute social jetlag augments morning blood pressure surge: a randomized crossover trial

Although social jetlag (SJL) is generally considered a chronic condition, even acute SJL may have unfavorable effects on the cardiovascular system. We focused on the acute effects of SJL on morning blood pressure (BP) surge. This randomized crossover trial recruited 20 healthy men. In the SJL trial, participants delayed their bedtime by three hours on Friday and Saturday nights. Participants in the control (CON) trial implemented the same sleep-wake timing as on weekdays. Pre- and post-intervention measurements were performed to evaluate resting cardiovascular variables on Friday and Monday mornings, respectively. The ambulatory BP was automatically measured during the sleep and awake periods for 2 h after the participant woke up at night before pre- and post-intervention measurements. SJL (average mid-sleep time on weekends – average mid-sleep time on weekdays) occurred only in the SJL trial (SJL: 181 ± 24 min vs. CON: 8 ± 47 min). Carotid-femoral pulse wave velocity (cfPWV) and morning BP surge on Monday in the SJL trial were significantly higher than those on Friday in the SJL trial (cfPWV: P = 0.001, morning BP surge: P < 0.001), and those on Monday in the CON trial (cfPWV: P = 0.007; morning BP surge: P < 0.001). Furthermore, a significant positive correlation was found between ΔcfPWV and Δmorning BP surge (R = 0.587, P = 0.004). These results suggest that even acute SJL augments morning BP surge. This phenomenon may correspond to increased central arterial stiffness.State the details of Clinical Trials: Name: Effect of acute social jetlag on risk factors of lifestyle-related diseases. URL: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000053204. Unique identifier: UMIN000046639. Registration date: 17/01/2022